US3653481A

US3653481A - Electrical/electronic coin or token indentification system

Info

Publication number: US3653481A
Application number: US36116A
Authority: US
Inventors: Ronald Stanley George Boxall; Anthony Charles Dennes
Original assignee: Mars Inc
Current assignee: Mars Inc
Priority date: 1967-07-17
Filing date: 1970-05-11
Publication date: 1972-04-04
Anticipated expiration: 1989-04-04
Also published as: GB1246622A; DE1774568C3; DE1774568A1; BE738920A; FR1605182A; CH508954A; DE1774568B2; CH488232A; CA922399A

Abstract

Two coin sensing devices are disclosed suitable for use in automatic vending machines. In both devices a coin is subjected to two separate tests and only if both of these tests are passed is the coin accepted. In the first of these devices a coin is caused to roll down a slope passing in succession two photoelectric sensors. A portion of the pathway between the two sensors lies in a magnetic field in which the coin is subjected to eddy current braking forces characteristic of the resistivity of the coin and, hence, the material of which it is made. The time taken to pass between the two sensors is measured as the first test. Measurement is also made of the time for which the second of these photoelectric sensors is occluded by the coin. This, the second test measures a quantity dependent on the diameter of the coin. Both measurements are compared electronically with predetermined standard results for acceptable coins. If both of these tests are passed the coin is recorded electronically in a totaliser and passed to an accepted-coin receptacle. In the second of these devices, a coin is rolled down a slope through a magnetic field which causes eddy current braking of the coin. A portion of the slope is interrupted by a trap through which the coin, if acceptable, will fall. A plastic coin will not be subjected to eddy current braking and will pass over the trap and continue down the slope and be rejected. The coin that falls through the trap passes a photoelectric sensor and impinges on a transducer. The time taken to fall past the photoelectric sensor is measured and is the subject of the first test. The impact of the coin on the transducer causes deflection of a moving part and this deflection which is dependent on the momentum of the coin, is measured. This measurement is used in the second test. In the two tests the measurements are compared electronically with predetermined standard results for acceptable coins. An electronic circuit is disclosed whereby the device can be programmed to examine and totalize three different denominations of coins.

Description

United States Patent Boxall et al.

[451 Apr.4,1972

[54] ELECTRICAL/ELECTRONIC COIN OR TOKEN INDENTIFICATION SYSTEM [72] Inventors: Ronald Stanley George Boxall, Bracknell; Anthony Charles Dennes, Winnersh, both of England [73] Assignee: Mars Incorporated, McLean, Va.

[22] Filed: May 11, 1970 [211 App]. No.: 36,116

Related U.S. Application Data [63] Continuation of Ser. No. 745,500, July 17, 1968,

Primary ExaminerStanley H. Tollberg Attorney-Davis, Hoxie, Faithful & Hapgood [57] ABSTRACT Two coin sensing devices are disclosed suitable for use in automatic vending machines. In both devices a coin is subjected to two separate tests and only if both of these tests are passed is the coin accepted.

In the first of these devices a coin is caused to roll down a slope passing in succession two photoelectric sensors. A portion of the pathway between the two sensors lies in a magnetic field in which the coin is subjected to eddy current braking forces characteristic of the resistivity of the coin and, hence, the material of which it is made. The time taken to pass between the two sensors is measured as the first test. Measurement is also made of the time for which the second of these photoelectric sensors is occluded by the coin. This, the second test measures a quantity dependent on the diameter of the coin. Both measurements are compared electronically with predetermined standard results for acceptable coins. If both of these tests are passed the coin is recorded electronically in a totaliser and passed to an accepted-coin receptacle.

In the second of these devices, a coin is rolled down a slope through a magnetic field which causes eddy current braking of the coin. A portion of the slope is interrupted by a trap through which the coin, if acceptable, will fall. A plastic coin will not be subjected to'eddy current braking and will pass over the trap and continue down the slope and be rejected. The coin that falls through the trap passes a photoelectric sensor and impinges on a transducer. The time taken to fall past the photoelectric sensor is measured and is the subject of the first test. The impact of the coin on the transducer causes deflection of a'moving part and this deflection which is dependent on the momentum of the coin, is measured. This measurement is used in the second test. In the two tests the measurements are compared electronically with predetermined standard results for acceptable coins.

An electronic circuit is disclosed whereby the device can be programmed to examine and totalize three different denominations of coins.

34 Claims, 5 Drawing Figures Patented April 4, 1972 3,653,481

4 Sheets-Sheet 1 INVENTORS RONALD $76. BOXALL ANTHONY C. DEA/IVES? #770 NEXS' Patented April 4, 1972 4 Sheets-Sheet 2 I l I INVENTORJ RONALD 5.6 eoxnu A .TI'ORNEVS Patented April 4, 1972 3,653,481

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ELECTRICAL/ELEGTRONIC COIN OR TOKEN INDENTIFICATION SYSTEM This is a continuation of application Ser. No. 745,500 filed July 17, l968,now abandoned.

The present invention relates to a sensing device for detecting coins. The device is suitable for use in coin-freed vending machines.

According to the present invention there is provided a sensing device for detecting coins or tokens including a sensor, a passageway along which coins or tokens can pass, the sensor being actuated by the passage of a coin or token in the passageway and providing to a circuit a signal indicative of the time taken for the coin to pass the sensor, the circuit including means for comparing the characteristic of the signal from the sensor with the signal characteristic for an acceptable coin or token to within a predetermined tolerance and means for providing a signal to indicate whether or not the signal from the sensor is within the predetermined tolerance.

The signal indicative of whether or not the signal from the sensor is within the predetermined tolerance can be used to operate a totalizer, and it can be used to cause movement of a guide track selectively to convey coins either to an accepted coin box or to a rejected coin box.

A magnetic field may be provided in part of the passageway to cause eddy current braking of the coin, the magnitude of the eddy current braking depends, among other things, upon the material from which the coin is made.

The time taken for the coin to pass the sensor in this case will therefore depend on the material from which the coin is made in addition to the dimensions of the coin. Thus, with this arrangement or more sensitive test of the coin is achieved.

The accuracy of the device can be improved by applying another test to the coin. In one preferred arrangement, the passageway includes in the region of the magnetic field, two sensors responsive to the presence of the coins. The time taken by a coin to pass between the two sensors is compared with a standard time for acceptable coins.

In another preferred arrangement, a transducer is provided and the passageway is so arranged that a coin inserted in the device strikes the transducer. The duration of the deflection of the transducer caused by the impact of the coin is dependent on the momentum of the coin and will be a characteristic of the denomination of the coin for a given device.

Embodiments of the invention will now be described by way of examples with reference to the accompanying drawings in which:

FIG. 1 shows a side elevation part cut away of a coin sensing device formed in accordance with this invention.

FIG. 2 shows a section of the coin sensing device of FIG. 1 taken along the lines II ll.

FIG. 3 shows a block circuit diagram of the sensing device of FIG. 1.

FIG. 4 shows a side elevation, part cut away, of a coin sensing device formed in accordance with another embodiment of this invention and FIG. 5 shows a circuit block diagram of the sensing device of FIG. 4.

Throughout this specification and in the appended claims the term coin" is intended to mean genuine coins, tokens, counterfeit coins, slugs, washers and any other items which may be used by persons in an attempt to operate coin operated devices.

Referring to FIGS. 1 and 2, there is shown one form of a coin sensing device 11 embodying this invention. A back member 12 is provided at its upper end with lugs 13 and a from member 14 is provided at its upper end with lugs 15. The

lugs

13 and 15 are held together by a pin 16 whereby the front member is pivotally connected to the back member. A lever 17 is pivotally connected to the back member and one end of 70 the lever 17 engages one of the lugs 15. The other end of the lever 17 is provided with a handle 18. The front member 14 carries an inclined track 19.

A permanent magnet 20 is mounted in a hole in the back member 12 and carried by an arm 21 which is pivotally connected to the back member. A projection 22 from the front member engages the arm 21. Depressing the handle 18 of the lever 17 lifts the front member 14 up and away from the back member 12. The projection 22 engages the arm 21 which moves the magnet 20 rearwardly away from the front of the back member 12.

An escapement 23 is mounted on an am 24 pivotally connected to the back member 12. The escapement passes through a slot in the back member and projects into the space between the front and back members. A solenoid 25 is provided on the back member which, when energized, attracts the arm 24 and retracts the escapement through the back member 12.

At the top of the front member 14 is provided a coin-receiving chute 14'. When a coin of ferrous material is placed in the device it is passed from the coin-receiving chute 14' to a region of the magnet 20 to which it is attracted and retained. Depressing the lever 17 moves the front member 14 and track 19 forwardly and retracts the magnet 20 behind the back member 12 causing the coin to be removed from the magnet by the back member, the coin falling to the bottom of the device and into a rejection receptacle.

The escapement 23 is at such an angle to the inclined track 19 that coins of different diameters start from different positions along the track 19. Large coins start from higher up the track than small coins. In this way there is a greater differential in the times taken by coins of different diameters to pass down the track 19.

In the back member 12 opposite the inclined track 19 there are two

photosensitive transistors

26 and 27. Gallium arsenide light sources (not shown) are located on the front member 14 opposite the

photosensitive transistors

26 and 27 to provide a light beam which is interrupted by the passing of a coin. On the front member between the

photosensitive transistors

26, 27 there is a magnet 28. A coin inserted in the machine is held on the inclined track 19 opposite the magnet 20 by the escapement 23. In this position the coin covers the photosensitive transistor 26 which emits a signal when thus covered, the signal being fed through a delay to energize the solenoid 25. The escapement is operated and if the coin is of a non-ferrous material it rolls down the track 19 passing the

photosensitive transistors

26, 27 and the magnet 28. The magnetic field of the magnet 28 gives rise to eddy currents in the coin. The eddy currents thus produced give rise to a magnetic field which interacts with the magnetic field of the magnet 28 causing a braking force to act on the coin. The magnitude of the eddy currents and thus the magnitude of the braking force depends on the resistivity of the material from which the coin is made. Hence, the time taken by a coin to pass between the sensors is a characteristic of the denomination of the coin. Similarly, the velocity of the coin as it passes the photosensitive transistor 27 at the lower end of the inclined track 19 will be characteristic of the denomination of the coin because the time taken for the coin to pass this photosensitive transistor depends upon the coins velocity and diameter. Signals from the two

transistors

26 and 27 are fed to a circuit in which the time taken for the coin to pass between the transistors and the time taken for the coin to pass the transistor 27 are compared with predetermined standard times taken by legitimate coins which the machine is programmed to accept. If the times taken are within a predetermined tolerance, a signal is passed from the circuit to a solenoid 29 mounted on the back member 12.

A guide track 30 is mounted on an arm 31 which is pivotally connected to the back of the back member 12. The guide track 30 passes through a slot in the back member 12 and projects to the front member 14. Unacceptable coins rolling off the end of the guide track 19 fall on to the guide track 30 when the solenoid is not energized. Coins rolling along guide track 30 pass to a reject coin receptacle 32. If the coin passing through the coin sensing device is acceptable, the solenoid 29 is energized effecting withdrawal of the guide track 30 through the back member 12 and the coins fall past the guide track into an acceptance box (not shown).

Referring now to FIG. 3, this shows a circuit diagram of the coin-sensing device of FIG. 1. The outputs of the

photosensitive transistors

26 and 27 are passed to a bi-stable circuit 33. The photosensitive transistors give an output signal whenever a coin passes in front of them. The signal from photosensitive transistor 26 triggers the bi-stable circuit 33 to provide a signal at its output. This signal is terminated by the presence of a signal from the photosensitive transistor 27. Thus the duration of the signal from the bi-stable circuit 33 is the time taken for the coin to pass between

photosensitive transistor

26 and 27.

The output from the bi-stable circuit and the output from the photo-sensitive transistor 27 are fed to

circuits

34, 35 and 36. These circuits are for penny, threepenny and sixpenny pieces respectively. Each circuit includes four

monostable circuits

37, 38, 39 and 40 which are Eccles-Jordan monostable circuits. The output from the bi-stable circuit is connected to two of the

monostable circuits

37 and 38 and the output of the photosensitive transistors 27 is connected to two of the monostable circuits 39 and 40. On receiving a signal at their inputs, the monostable circuits provide a signal at their outputs, the duration of which is predetermined by the value of a variable resistor. The

monostable circuits

37, 38, 39 and 40 are provided with

coincidence gates

41, 42, 43 and 44 respectively. The output of the bi-stable circuit 33 is connected to the

coincidence gates

41 and 42 associated with

monostable circuits

37 and 38 and the output of the photosensitive transistor 27 is connected to the

coincidence gates

43, 44 associated with the monostable circuits 39 and 40.

The monostable circuit 37 provides a signal, the duration of which is the lower limit tolerance for a penny coin to pass between

photosensitive transistors

26 and 27. This is compared with the time taken by the coin which is passing through he machine to pass between

photosensitive transistors

26 and 27 in the coincidence gate and a signal is passed to a memory 45 only if the duration of the signal from the bi-stable circuit is greater than the signal from the mono-stable circuit 37. The memory 45 holds the signal passed to it from the coincidence gate 41.

Similarly, the monostable circuit 38 provides a signal, the duration of which is the upper tolerance limit for the time taken for a penny coin to pass through

photosensitive transistors

26 and 27 and a signal is passed from the coincidence gate to a memory 46 when the duration of the signal from the bi-stable circuit 33 is less than the duration of the signal from the monostable circuit 38.

Coincidence gates

43 and 44 pass signals to their associated

memories

47, 48 whenever the duration of the signal from the photosensitive transistor 27 is less than the upper limit for the time taken for a penny piece to pass the photosensitive transistor 27 and greater than the lower limit for a penny piece to pass the photosensitive transistor 27. The output of

memories

45, 46, 47 and 48 are fed to an AND gate 49 which provides an output whenever all the conditions for a penny piece are satisfied. This output is fed to a penny totalizer 50 and to a NOR gate 51. Similarly, the threepenny circuit 35 provides an output signal to the NOR gate 51 and a threepenny totalizer 52 whenever the signals from the photosensitive transistors satisfy the requirements for a threepenny piece and the sixpenny circuit 36 provides an output signal to the NOR gate 51 and a sixpenny totalizer 53 whenever the signals from the photosensitive transistor satisfy the requirements for a sixpenny piece. The presence of a signal at any of the inputs of the NOR gate 51 provides a signal which energizes the coils of the acceptance solenoid 29.

When a coin is inserted in the coin-receiving chute 14' it is passed to the part of the inclined track 19 close to the magnet 20 where it is prevented from rolling down the guide track 19 by the escapement 23. In this position it covers the photosensitive transistor 26 which causes the solenoid 25 to be energized after a suitable delay of time. The escapement 23 is thus removed from the path of the coin and if the coin is of non-ferrous material it will roll down the inclined track 19. However, if the coin is of ferrous material it will be held by the magnet 20. To release the coin thus held, the handle 18 of the lever 17 is depressed which causes the guide track 19 and from member 14 to move away from the back member 12. The guide track 19 is thus removed from beneath the coin. The magnet 20 is retracted through the hole in the back member 12 and thus moves away from the coin. The coin is no longer held by the magnet and falls to the bottom of the machine into the reject coin receptacle 32. In this way a coin of ferrous material is prevented from passing the magnet 28 and thus cannot become held by the magnet 28 and obstruct the passage of acceptable coins.

Non-ferrous coins will pass down the inclined track 19 and be subjected to an eddy current braking force which depends on the material from which they are made. The time taken by the coin to pass between the two

photosensitive transistors

26 and 27 and the time taken by the coin to pass photosensitive transistor 27 are characteristic of the coin. These times are compared by the circuits of the device with the values for the coins which the device is designed to accept and if they are within a predetermined tolerance of these values, the solenoid 29 is energized and the guide track 30 is withdrawn into the back member 12. The coin which falls off the end of the inclined guide track 19 passes the guide track 30 into the coin acceptance box.

If, however, the times taken by the coin did not correspond to those of a coin which the device is to accept solenoid 29 is not energized and the coin falls on to guide track 30 which carries the coin to the reject coin box 32.

FIG. 4 shows another coin sensing device. A coin receiving chute 60 carries coins to the upper end of an inclined track 61. A pin 62 projects into the path of coins passing from the chute 60 to the track 61 and deflects them against a wall 63 at the upper end of the track. A magnet 64 is located beside the track 61. Coins fed into the chute 60 are thrown against the wall 63 by the pin 62 so that they roll down the track 61 starting with a velocity that is substantially zero. As they roll down the track 61 they pass the permanent magnet 64. Eddy currents generated in the coins by the permanent magnet 64 give rise to a braking force on the coin.

The track 61 is terminated by a vertical passage 65 and a track 66 continues at the same angle as the inclined track 61 from the side of the vertical passage 65 opposite the inclined track 61. Plastic tokens which are inserted in the device will not be slowed down by eddy current braking and will be travelling at high velocity at the bottom of the inclined track 61. Thus they will pass over the vertical passage 65 and be carried by the guide track 66 to a reject coin box. A metal coin will be slowed down by eddy current braking and will fall down the vertical passage 65.

A photosensitive transistor 67 is located at the side of the vertical passage. When a coin passes in front of the photosensitive transistor 67, the photosensitive transistor emits a signal which is fed to a circuit.

At the bottom of the vertical passage 65 there is an anvil 68 of a linear transducer 69. The surface of the anvil is inclined. Coins passing down the vertical passage 65 will impinge on the anvil 65. The deflection of the anvil is dependent on the momentum of the coin and therefore the time during which the anvil is displaced is also dependent upon the momentum of the com.

A guide track 70 is mounted on the arm 71 which is pivotally attached to a back member 72 which supports the other parts of the device. A solenoid 73 is located near to the guide track 70. A further guide track 74 is attached to the back member 72. The surface of the anvil 68, the guide track 70 and the guide track 74 are aligned when the solenoid 73 is not energized. When the solenoid is energized the guide track 70 is moved out of line and coins passing from the inclined surface of the anvil 68 fall past the guide track 70 into an acceptance box 75.

FIG. 5 shows the circuits of the embodiment of FIG. 4 which is similar to that shown in FIG. 3 and only those parts that are different will be described. In this case the signal from the transducer alone is passed to a bi-stable circuit 76 which provides a signal at its output whenever there is a signal at its input. Thus the bistable circuit provides a signal which lasts for the duration of the deflection of the anvil. The output of the bi-stable circuit is connected to the inputs of two monostable circuits of each of the

coin piece circuits

34, and 36. The output of photosensitive transistor 67 is similarly connected to the inputs of two monostable circuits.

The circuits of FIG. 4 compare the time the coin takes to pass the photosensitive transistor 67 and the time the anvil 68 is deflected with the times for acceptable coins. If the times for the coin are within a predetermined tolerances the solenoid 73 is energized.

A coin entering the coin-receiving chute 60 is passed to the inclined track 61 and rolls down it, being slowed down by the eddy current braking force as it passes the magnet 64. Its speed as it falls down the vertical passage 65 depends on its resistivity, surface area (due to the frictional force between the coin and the side of the inclined track) and moment of inertia (since it moves off from rest). Thus the speed with which it passes the photosensitive transistor 67 will depend on the denomination of the coin. The time taken by the coin to pass the transistor 67 will depend on these factors together with the coins diameter and therefore the duration of the signal from the photosensitive transistor will be characteristic of the denomination of the coin in the device. The duration of the signal from the transistor is compared in the circuits with the duration of signals for coins of denominations which the device is to accept and, if it is within the predetermined tolerance, signals are stored in memories of the circuits.

The coin then falls on the anvil 68 of the transducer 69 and a signal is given out by the transducer proportional to the deflection of the anvil. The deflection of the anvil will depend on the coins momentum and this will be characteristic of the denomination of the coin. The duration of the deflection will also be characteristic of the denomination of the coin. The duration of the deflection is compared with those for coins which the device is to accept and, if it is within the predetermined tolerance, signals are stored in memories of the circuit.

When all the memories for one denomination of coin hold stored signals the solenoid 73 is energized and the track 70 is moved to allow the coin on the surface of the anvil 68 to roll into the accepted coin box 75.

If the signals produced by the passing coin do not show it to be acceptable the solenoid 73 is not energized and the track 70 carries the coin to the track 74 whence it passes to the rejected coin box.

After the passage of each coin the memories are cancelled.

Thus the present invention provides a method of detecting and distinguishing coins of different denominations. The invention also provides a coin detector with no moving parts.

What is claimed is:

l. A sensing device for determining the authenticity of coins of an acceptable denomination comprising a passageway, sensor means for generating signals for each coin characteristic of at least two properties of a coin, means for determining whether each signal is a signal characteristic of the corresponding properties of an acceptable coin, means for indicating whether the coin is acceptable and means for providing a magnetic field in a region of the passageway through which a coin passes before reaching at least a portion of said sensor means.

2. A sensing device as defined in claim 1 including means for sensing a chordal dimension of the coin and providing a signal indicative of the dimension and means for comparing the dimension related signal with a signal characteristic of a corresponding chordal dimension of an acceptable coin.

3. A sensing device as defined in claim 1 wherein a sensor means comprises two sensors spaced apart in the direction of travel of the coin and wherein the signal generated by that means is indicative of the time taken by the coin to pass between the two sensors.

4. A sensing device as defined in claim 3 wherein the magnetic fieldis located between the two sensors.

5. A sensing device as defined in claim 4 in which the passageway includes an inclined portion, the coin moving down the inclined portion under the force of gravity.

6. A sensing device as defined in claim 5 including means for starting movement of the coin down the inclined portion at a predetermined velocity.

7. A sensing device as defined in claim 6 wherein the means for starting the movement of the coin includes an escapement adapted to arrest the coin at the top of the inclined portion and then release it from rest to pass down the inclined portion under the force of gravity.

8. A sensing device as defined in claim 7 wherein one of the sensors produces a signal when a coin is arrested by the escapement, the signal causing actuation of the escapement, to release the coin or token.

9. A sensing device as defined in claim 1 wherein the passageway includes an inclined portion, the coin moving down the inclined portion under the force of gravity.

10. A sensing device as defined in claim 9 including means for starting the movement of a coin down the inclined portion at a predetermined velocity.

11. A sensing device as defined in claim 9 including an escapement adapted to arrest the coin at the top of the inclined portion and then release it from rest to pass down the inclined portion under the force of gravity.

12. A sensing device as defined in claim 1 including a coin reject passage, second means for producing a magnetic field across the passageway, the second means being located upstream from the first mentioned means for providing a magnetic field, the second means being mounted on the sensing device for movement away from the passageway whereby a coin of highly magnetic material will adhere to the second means and be prevented from passing to the passageway and means for releasing the adhered coin into the coin reject passage.

13. A sensing device as defined in claim 4 including a coin reject passage, second means for providing a magnetic field across the passageway being mounted on the sensing device for movement away from the passageway whereby a highly magnetic coin entering the sensing device will be retained by the second means to prevent its passage through the passageway to the first mentioned means for providing a magnetic field, and means for releasing the retained magnetic coin into the coin reject passage.

14. A sensing device as defined in claim 1 including a coin reject passage and coin acceptance passage and coin direction control means, the coin direction control means normally being oriented to direct coins passing through the sensing device into the coin reject passage, said coin direction control means being actuated and moved into a position directing a coin into the coin acceptance passage by a signal from the coin acceptance indicating means when the signal indicates that an acceptable coin has passed through the sensing device.

15. A sensing device as defined in claim 1 wherein at least one sensor means includes a light source and a light sensing device.

16. A sensing device as defined in claim 4 wherein at least one sensor means includes a light source and a light sensing device.

17. A method of determining the authenticity of coins or tokens passing through a passageway comprising the steps of sensing a first property of the coin, sensing a second property of the coin providing at least two signals indicative of the first and second properties of the coin, comparing the signals with corresponding predetermined signals characteristic of properties of an acceptable coin and indicating whether the coin passing through the sensing device is acceptable.

18. A method as defined in claim 17 including the step of providing a magnetic field in a region of the passageway through which a coin passes during the sensing of one property.

19. A method as defined in claim 18 including wherein the first property of the coin is dimensional and wherein the second property of the coin is material dependent.

20. A method of determining the authenticity of coins or tokens passing through a passageway comprising the steps of sensing a chordal dimension of the coin, sensing a material dependent characteristic of the coin, providing a magnetic field across the passageway through which the coin passes prior to completion of the sensing of the material dependent characteristic, providing a first signal indicative of the chordal dimension, providing a second signal indicative of the material dependent characteristic, comparing the first and second signals with predetermined indicia indicative of corresponding characteristics of an acceptable coin and indicating whether the coin passing through the sensing device is acceptable.

21. A device for testing coins including a passageway along which coins can pass, a sensor which is actuated by a passing token in the passageway and which provides two alternative outputs, a first in the absence of a coin and a second in the presence of a coin, whereby with movement of a coin past the sensor the duration of the second output indicates the time taken by the coin to pass the sensor, means for comparing the duration of the second output with a standard, and means for producing a magnetic field are located beside the passageway in a region of the passageway through which a coin passes before reaching the sensor.

22. A device according to claim 21, including a second sensor which is actuated by a passing coin in the passageway, means for producing a magnetic field in a region of the passageway, means responsive to the first and second sensors to provide a signal indicative of the time taken by the coin to pass from the first sensor to the second sensor, and a further circuit adapted to receive the signal from the said responsive means and including means for comparing the signal with a standard 23. A device according to claim 21 in which the passageway includes an inclined portion, including a coin-releasing mechanism adapted to arrest the coin at the top of the inclined portion and then release it from rest to pass down the inclined portion.

24. A device according to claim 23, including a solenoid and in which a second sensor is actuated by a coin arrested by the coin-releasing mechanism, a signal from the sensor causing the solenoid to be energized to operate the coin-releasing mechanism and release the coin.

25. A device according to claim 21, including second means for producing a magnetic field located beside the passageway, upstream of the first said means for producing a magnetic field, the second means being mounted on an arm for movement away from the passageway, whereby a coin of ferrous material can be held by the second means and prevented from passing further down the passageway, and can be released by movement of the second means.

26. A device according to claim 21 in which the sensor is a photosensitive device with an associated light source.

27. A device for testing coins comprising means for producing a magnetic field in a region of a passageway along which coins can pass, first and second sensors responsive to the passage of a coin in the passage, and means for comparing with a standard the time taken by the coin to pass from the first sensor to the second sensor, the first and second sensors being so positioned relative to the means for producing the magnetic field that the time taken by the coin to pass from the first sensor to the second sensor is dependent on its interaction with the magnetic field.

28. A sensing device according to claim 27 in which the sensors are spaced apart in a direction to be traversed by the coin in sequence, the first sensor to be traversed initiating the said time measurement and the second completing the measurement after the coin has been subjected to the said magnetic field.

29. A sensing device according to claim 28 in which the said first sensor is traversed before the token has been subjected to the said magnetic field.

30. A sensing device according to claim 27 including tokenreleasing mechanism adapted to arrest the token at the top of the passageway and then release it from rest to pass down the passageway.

31. A sensing device according to claim 27 in which the sensors are photosensitive devices with associated light sources.

32. A method of testing a coin including the steps of allowing the coin to pass along a predetermined path through a magnetic field, sensing the time taken by the coin so subjected to the field to move a predetermined distance, and comparing the time so sensed with a standard time for an acceptable coin.

33. The method of claim 32 including the steps of providing a first signal from a sensor indicative of time taken for the coin to pass the sensor, comparing the first signal from the sensor with a standard and providing a second signal to indicate whether the first signal is within a predetermined tolerance of the standard.

34. A device for testing coins, including a passageway along which coins can pass, a sensor which is actuated by a passing coin in the passageway and which provides two alternative outputs, a first in the absence of a coin and a second in the presence ofa coin, whereby with movement of a coin past the sensor the duration of the second output indicates the time taken by the coin to pass the sensor, a first circuit means for comparing the duration of the second output with a standard, a transducer, a passageway to lead the coin to the transducer, the transducer providing a signal indicative of the time of displacement of an element thereof caused by an impinging coin a second circuit means for comparing the duration of the signal from the transducer with a standard, and connected to the first and second circuit means a third circuit means for indicating whether the coin is acceptable.

Claims

1. A sensing device for determining the authenticity of coins of an acceptable denomination comprising a passageway, sensor means for generating signals for each coin characteristic of at least two properties of a coin, means for determining whether each signal is a signal characteristic of the corresponding properties of an acceptable coin, means for indicating whether the coin is acceptable and means for providing a magnetic field in a region of the passageway through which a coin passes before reaching at least a portion of said sensor means.

4. A sensing device as defined in claim 3 wherein the magnetic field is located between the two sensors.

22. A device according to claim 21, including a second sensor which is actuated by a passing coin in the passageway, means for producing a magnetic field in a region of the passageway, means responsive to the first and second sensors to provide a signal indicative of the time taken by the coin to pass from the first sensor to the second sensor, and a further circuit adapted to receive the signal from the said responsive means and including means for comparing the signal with a standard.

23. A device according to claim 21 in which the passageway includes an inclined portion, including a coin-releasing mechanism adapted to arrest the coin at the top of the inclined portion and then release it from rest to pass down the inclined portion.

30. A sensing device according to claim 27 including token-releasing mechanism adapted to arrest the token at the top of the passageway and then release it from rest to pass down the passageway.

34. A device for testing coins, including a passageway along which coins can pass, a sensor which is actuated by a passing coin in the passageway and which provides two alternative outputs, a first in the absence of a coin and a second in the presence of a coin, whereby with movement of a coin past the sensor the duration of the second output indicates the time taken by the coin to pass the sensor, a first circuit means for comparing the duration of the second output with a standard, a transducer, a passageway to lead the coin to the transducer, the transducer providing a signal indicative of the time of displacement of an element thereof caused by an impinging coin a second circuit means for comparing the duration of the signal from the transducer with a standard, and connected to the first and second circuit means a third circuit means for indicating whether the coin is acceptable.